tests(): add test to verify new way of creating classes

src/@ionic-native/core/ionic-native-plugin.spec.ts

@@ -0,0 +1,69 @@
+// This is to verify that new (FileTransfer.getPlugin)() works
+
+import { Plugin, CordovaInstance } from './decorators';
+import { checkAvailability } from './plugin';
+import { IonicNativePlugin } from './ionic-native-plugin';
+
+class FT {
+  hello(): string {
+    return 'world';
+  }
+}
+
+(window as any).FileTransfer = () => new FT();
+
+@Plugin({
+  plugin: 'cordova-plugin-file-transfer',
+  pluginRef: 'FileTransfer',
+  repo: '',
+  pluginName: 'FileTransfer'
+})
+export class FileTransfer extends IonicNativePlugin {
+  create(): FileTransferObject {
+    let instance: any;
+    if (checkAvailability(FileTransfer.getPluginRef(), null, FileTransfer.getPluginName()) === true) {
+      instance = new (FileTransfer.getPlugin())();
+    }
+    return new FileTransferObject(instance);
+  }
+}
+
+export class FileTransferObject {
+
+  constructor(public _objectInstance: any) {
+    console.info('Creating a new FileTransferObject with instance: ', _objectInstance);
+  }
+
+  @CordovaInstance({ sync: true })
+  hello(): string { return; }
+
+}
+
+describe('Mock FileTransfer Plugin', () => {
+
+  let plugin: FileTransfer,
+    instance: FileTransferObject;
+
+  beforeAll(() => {
+    plugin = new FileTransfer();
+    instance = plugin.create();
+  });
+
+  it('should create a new FileTransfer plugin instance', () => {
+    expect(plugin instanceof FileTransfer).toBeTruthy();
+  });
+
+  it('should create new FileTransferObject instance', () => {
+    expect(instance instanceof FileTransferObject).toBeTruthy();
+  });
+
+  it('FileTransferObject instance should have _objectInstance property', () => {
+    expect(instance._objectInstance).toBeDefined();
+  });
+
+  it('FileTransferObject.hello should return world', () => {
+    console.info('instance hello is', instance.hello());
+    expect(instance.hello()).toEqual('world');
+  });
+
+});